1. Field of the Invention
The present invention relates generally to a technique of recognizing a connection between a computer main unit and an input/output (IO) expansion device and, more particularly, to a computer, an IO expansion device and a method for recognizing a connection of IO expansion device to realize connection or disconnection between a computer main unit and an IO expansion device on a partition-by-partition basis.
2. Description of the Related Art
In recent years, the development of multiprocessor-type computer servers has been pursued. There is now a tendency to increase the scale of multiprocessor-type computer servers. There is also a demand for server systems capable of fine partitioning for operating a plurality of CPUs on a job-by-job basis and capable of offering various services.
Because of the demand for such servers and systems, recent external IO functions need compatibility with flexible partitioning. In some cases, a function deficiency occurs at the time of fine partitioning if IO functions in a computer main unit alone are used. Therefore, there is a need to add IO functions by providing an IO function expansion device such as PCI_Box.
FIG. 10 is a diagram showing connections between a computer main unit and function expansion devices used in a conventional system. Each IO function expansion device is a PCI_Box. Referring to FIG. 10, the computer main unit 60 includes a supervisory control unit (management board (MMB)) 61 and an IO unit (IOU) 62.
MMB 61 has a CPU 100 and a controller 101 and performs supervisory control of the connection between the IOU 62 and PCI_Box (#0) 8 or PCI_Box (#N) 9. The number in the parentheses of PCI_Box (#0) 8 and the number in the parentheses of PCI_Box (#N) 9 are each an ID number for uniquely identifying the PCI_Box.
The IOU 62 has an IO driver/receiver (IO DV/RV) 102 and a connector 103. The IOU 62 is connected to each PCI_Box by a PCI_Box connection cable 90 indicated by a dotted line and the connector 103. The IO DV/RV 102 in the IOU 62 transmits a main 10 signal from the computer main unit 60 to each PCI_Box.
The PCI_Box connection cable 90 is formed of a main signal line 91 and a PCI_Box implementation signal line 92. The main signal line 91 is a signal line used when the IO main signal is transmitted to one PCI_Box from the computer main unit 60. The PCI_Box implementation signal line 92 is a signal line used when a PCI_Box implementation signal indicating a state where one PCI_Box is connected to or disconnected from the IOU 62 is transmitted from the PCI_Box to the MMB 61. The PCI_Box implementation signal line 92 is a one-way serial communication line.
Each of the PCI_Box (#0) 8 and PCI_Box (#N) 9 has an IO DV/RV 104 and a connector 105. A PCI card is connected to the IO DV/RV 104.
In the conventional system shown in FIG. 10, one PCI_Box (#0) 8 or PCI_Box (#N) 9 is used in correspondence with a unit partition.
Supervisory control processing in a case where the PCI_Box (#0) 8 is connected to the IOU 62 will be described by way of example. When the connector 105 of the PCI_Box (#0) 8 is connected to the connector 103 in the IOU 62 via the PCI_Box connection cable 90, the PCI_Box implementation signal is transmitted from the PCI_Box (#0) 8 to the controller 101 in the MMB 61 via the PCI_Box implementation signal line 92.
The controller 101 in the MMB 61 receives the PCI_Box implementation signal from the PCI_Box (#0) 8 and establishes a connection between the IOU 62 and the PCI_Box (#0) 8.
When the MMB 61 detects interruption of the PCI_Box implementation signal from the PCI_Box (#0) 8, it determines that a connection abnormality has occurred.
A composite computer console apparatus arranged to implement a plurality of console input/output devices in one unit is described, for example, in Japanese Patent Laid-Open No. 59-81752. Also, a data bus check method of performing detection for checking whether or not there is an abnormality in a data bus in a control apparatus configured on a function-by-function basis is described, for example, in Japanese Patent Laid-Open No. 2-133848.
In the conventional system shown in FIG. 10, the PCI_Box (#0) 8 or the PCI_Box (#N) 9 has no function adapted for partitioning. In a conventional server, for example the PRIMEPOWER series (PRIMEPOWER: a registered trademark of Fujitsu Co., Ltd.), a system in which one PCI_Box is used in correspondence with a unit partition, as in the case of the conventional system shown in FIG. 10, is also adopted. No system capable of an operation including partitioning in a PCI_Box has been provided.
In the conventional system shown in FIG. 10, the PCI_Box implementation signal transmitted from each PCI_Box to the computer main unit 60 is transmitted over a one-way communication line, for example, the PCI_Box implementation signal line 92. Therefore, there is a problem that when a communication abnormality occurs between the computer main unit 60 and one PCI_Box, the time taken to identify a fault point corresponding to the cause of communication abnormality is considerably long.
For example, in the conventional method shown in FIG. 10, it is difficult to ascertain in which one of the communication paths in the PCI_Boxes, the communication paths between the PCI_Boxes and the IOU 62, the communication path in the IOU 62 and the communication path between the IOU 62 and the MMB 61 a fault point relating to communication abnormality exists.
In a case where a system different from the conventional system and capable of an operation including partitioning in a PCI_Box is adopted, a process for connection between the computer main unit and PCI_Boxes is required in which connections on a partition-by partition basis are established in a state where a connection between the computer main unit side and the PCI_Box side is established.
When a connection is added or removed between the computer main unit and the PCI_Boxes, there is a need to enable connection or disconnection on a partition-by partition basis.
There is also a need to enable connection or disconnection in correspondence with a partition to be added or removed, while partitions used in operation are maintained. Further, there is a need for a device for preventing an erroneous connection between the computer main unit and the PCI_Boxes to avoid an error in the operation of the system.